Fluorinated polymers are known to have properties of water repellency, oil repellency and dirt prevention due to the presence of fluorine atoms. Furthermore, because fluorinated polymers display excellent transparency in a wavelength range from visible to near infrared, in recent years, with the development of optical communication systems, such fluorinated polymers have been investigated for potential use as the materials for a variety of optical communication components and optical devices. For example, an aromatic polyester with tetrafluorophthalic acid as a structural unit is disclosed in patent reference 1, and a fluorinated aromatic polyester carbonate resin is disclosed in patent reference 2. Furthermore, patent reference 3 discloses the use of a fluorinated polyimide resin as an optical waveguide.
Fluorinated polymers are produced by a condensation or an addition reaction of a nucleophile such as a diamine compound or a diol and a nucleophile target compound such as a carboxylic acid or an isocyanate, wherein at least one of the reactants is a fluorinated compound.
However, when an attempt is made to introduce fluorine using a fluorinated aromatic diamine or a fluorinated aromatic diol as the fluorinated compound, then in those cases where the amino group or the hydroxyl group is bonded directly to the aromatic ring, the nucleophilic reactivity of the nitrogen atom or the oxygen atom of the fluorinated aromatic diamine or the fluorinated aromatic diol decreases markedly due to the high electronegativity and high electron-withdrawing property of the fluorine atom. As a result, the reaction requires high temperatures and prolonged heating, and consequently problems such as coloring arise, and the molecular weight of the polymer does not increase sufficiently.    1. Japanese Unexamined Patent Application, First Publication No. Sho 63-172728    2. Japanese Unexamined Patent Application, First Publication No. Hei 10-081738    3. Japanese Unexamined Patent Application, First Publication No. 2000-292635
An object of the present invention is to provide a fluorinated polymer of adequate molecular weight with excellent transparency in a wavelength range from visible to near infrared. Furthermore, another object of the present invention is to provide a method of producing such a polymer.